In the drilling, completion, and stimulation of hydrocarbon-producing wells, a variety of downhole tools are used. For example, during hydraulic fracturing operations it is required to seal portions of a wellbore to allow fluid to be pumped into the wellbore and forced out under pressure into surrounding subterranean formations. Wellbore isolation devices, such as packers, bridge plugs, and fracturing plugs (alternately referred to as “frac” plugs) are designed for this purpose.
Typical wellbore isolation devices include a body and a sealing element disposed about the body and used to generate a seal within the wellbore. Upon reaching a desired location within the wellbore, the wellbore isolation device is actuated by hydraulic, mechanical, electrical, or electromechanical means to cause the sealing element to expand radially outward and into sealing engagement with the inner wall of the wellbore, or alternatively with casing lining the wellbore, or the inner wall of other piping or tubing positioned within the wellbore. Upon setting the sealing element, the migration of fluids across the wellbore isolation device is substantially prevented, which fluidly isolates the axially adjacent upper and lower sections of the wellbore.
At elevated pressures and temperatures common to downhole environments, the material used to form the sealing element tends to creep and extrude through small gaps provided by various components of the wellbore isolation device. Excessive extrusion of this material reduces the sealing capacity of the sealing element, which could result in well fluids leaking past the wellbore isolation device.